Input: xpad - fix Xbox One rumble stopping after 2.5 secs

Unlike previous Xbox pads, the Xbox One pad doesn't have "sticky" rumble
packets. The duration is encoded into the command and expiration is handled
by the pad firmware.

ff-memless needs pseudo-sticky behavior for rumble effects to behave
properly for long duration effects. We already specify the maximum rumble
on duration in the command packets, but it's still only good for about 2.5
seconds of rumble. This is easily reproducible running fftest's sine
vibration test.

It turns out there's a repeat count encoded in the rumble command. We can
abuse that to get the pseudo-sticky behavior needed for rumble to behave as
expected for effects with long duration.

By my math, this change should allow a single ff_effect to rumble for 10
minutes straight, which should be more than enough for most needs.

Signed-off-by: Cameron Gutman <aicommander@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 19886dbfe18d918cc64089dece01d4e2b86fdc1d..6d949965867190458abaa653636ed4ab6702a4aa 100644 (file)
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -1045,9 +1045,9 @@ static int xpad_play_effect(struct input_dev *dev, void *data, struct ff_effect
                packet->data[7] = 0x00;
                packet->data[8] = strong / 512; /* left actuator */
                packet->data[9] = weak / 512;   /* right actuator */
-               packet->data[10] = 0xFF;
-               packet->data[11] = 0x00;
-               packet->data[12] = 0x00;
+               packet->data[10] = 0xFF; /* on period */
+               packet->data[11] = 0x00; /* off period */
+               packet->data[12] = 0xFF; /* repeat count */
                packet->len = 13;
                packet->pending = true;
                break;